U.S. patent application number 16/753084 was filed with the patent office on 2020-10-08 for method for manufacturing battery module.
This patent application is currently assigned to LG Chem, Ltd.. The applicant listed for this patent is LG Chem, Ltd.. Invention is credited to Yoon Gyung Cho, Yang Gu Kang, Hyun Suk Kim, Eun Suk Park, Hyoung Sook Park, Sang Min Park, Se Woo Yang, Young Jo Yang.
Application Number | 20200321565 16/753084 |
Document ID | / |
Family ID | 1000004970269 |
Filed Date | 2020-10-08 |
United States Patent
Application |
20200321565 |
Kind Code |
A1 |
Park; Eun Suk ; et
al. |
October 8, 2020 |
Method for Manufacturing Battery Module
Abstract
A method for manufacturing a battery module is disclosed herein.
In some embodiments, a method for manufacturing a battery module
which comprises a module case, in which an internal space is formed
by a bottom plate and sidewalls, and an injection port is formed in
the bottom plate or the sidewalls; a plurality of battery cells
existing in the internal space; and a resin layer in contact with
the bottom plate or the sidewalls while being in contact with the
battery cells, the method including attaching a tape to cover the
injection port of the bottom plate or the sidewalls; mounting an
injection device of a resin composition such that the injection
device is mounted on the injection port while penetrating the tape,
and injecting the resin composition into the mounted injection
device. The method provides a simple process and at low cost
without occurrence of a reverse discharge phenomenon.
Inventors: |
Park; Eun Suk; (Daejeon,
KR) ; Yang; Se Woo; (Daejeon, KR) ; Cho; Yoon
Gyung; (Daejeon, KR) ; Kang; Yang Gu;
(Daejeon, KR) ; Kim; Hyun Suk; (Daejeon, KR)
; Park; Hyoung Sook; (Daejeon, KR) ; Park; Sang
Min; (Daejeon, KR) ; Yang; Young Jo; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Chem, Ltd. |
Seoul |
|
KR |
|
|
Assignee: |
LG Chem, Ltd.
Seoul
KR
|
Family ID: |
1000004970269 |
Appl. No.: |
16/753084 |
Filed: |
November 5, 2018 |
PCT Filed: |
November 5, 2018 |
PCT NO: |
PCT/KR2018/013295 |
371 Date: |
April 2, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 2/029 20130101;
B29C 65/50 20130101; H01M 2/0245 20130101 |
International
Class: |
H01M 2/02 20060101
H01M002/02; B29C 65/50 20060101 B29C065/50 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2017 |
KR |
10-2017-0172480 |
Claims
1. A method for manufacturing a battery module which comprises a
module case, in which an internal space is formed by a bottom plate
and sidewalls, and an injection port is formed in the bottom plate
or the sidewalls; a plurality of battery cells existing in the
internal space; and a resin layer in contact with the bottom plate
or the sidewalls while being in contact with the battery cells.
comprising steps of: attaching a tape to cover the injection port
of the bottom plate or the sidewalls; mounting an injection device
of a resin composition such that the injection device is mounted on
the injection port while penetrating the tape; and injecting the
resin composition into the mounted injection device.
2. The method for manufacturing a battery module according to claim
1, wherein the injection port is formed along a total length of the
sidewalls or the bottom plate at a point that is 1/4 to 3/4 point
of along the total length from an end of the sidewalls or the
bottom plate.
3. The method for manufacturing a battery module according to claim
1, wherein the tape comprises a polyester film, an acrylic film, a
polyolefin film, paper, a cellulose-based polymer film, a
polystyrene film or a polycarbonate-based film.
4. The method for manufacturing a battery module according to claim
1, further comprising: prior to attaching the tape, forming a
penetrating auxiliary portion in the tape, the penetrating
auxiliary portion having a smaller size than that of the injection
port; or forming the penetrating auxiliary portion after the tape
is attached to cover the injection portion.
5. The method for manufacturing a battery module according to claim
4, wherein the injection device is mounted on the injection port
toward the penetrating auxiliary portion.
6. The method for manufacturing a battery module according to claim
1, wherein the injection of the resin composition is performed in a
state where a number of battery cells are present in the internal
space.
7. The method for manufacturing a battery module according to claim
1, further comprising: removing the tape after the resin
composition has been injected.
8. The method for manufacturing a battery module according to claim
1, wherein the resin composition to be injected has a room
temperature viscosity of 400 cP or less at a shear rate of
2.5/s.
9. The method for manufacturing a battery module according to claim
1, wherein the resin composition is a room temperature curing resin
composition.
10. The method for manufacturing a battery module according to
claim 1, wherein the resin composition comprises: a resin component
comprising an acrylic resin, an epoxy resin, a urethane resin, an
olefin resin, an EVA resin or a silicone resin; or one or more
precursors of the resins.
11. The method for manufacturing a battery module according to
claim 10, wherein the resin composition further comprises a
filler.
12. The method for manufacturing a battery module according to
claim 11, wherein the filler is present in a range of 50 to 2,000
parts by weight relative to 100 parts by weight of the resin
component or the one or more precursors.
Description
[0001] Cross-reference to related application(s)The present
application is a national phase entry under 35 U.S.C. .sctn. 371 of
International Application No. PCT/KR2018/013295, filed on Nov. 5,
2018, which claims priority from Korean Patent Application No.
10-2017-0172480, filed on Dec. 14, 2017, the disclosures of which
are incorporated by reference herein.
TECHNICAL FIELD
[0002] The present application relates to a method for
manufacturing a battery module.
BACKGROUND ART
[0003] The secondary battery includes a nickel cadmium battery, a
nickel hydride battery, a nickel zinc battery, or a lithium
secondary battery, and the like, where a typical example thereof is
a lithium secondary battery.
[0004] The lithium secondary battery mainly uses lithium oxides and
carbon materials as positive electrode and negative electrode
active materials, respectively. The lithium secondary battery
includes an electrode assembly in which a positive plate and a
negative plate coated with a positive electrode active material and
a negative electrode active material, respectively, are disposed
with a separator interposed therebetween, and an exterior material
in which the electrode assembly is sealed and housed together with
an electrolyte, which can be classified as a can type secondary
battery and a pouch type secondary battery depending on the kind of
the exterior material.
[0005] In this specification, a single secondary battery can be
referred to as a battery cell.
[0006] When used in medium and large devices such as automobiles or
energy storage systems, to increase capacity and power, a large
number of battery cells may be electrically connected to each other
to constitute a battery module or a battery pack.
[0007] For example, Patent Document 1 discloses a battery module
having excellent power relative to the volume while being
lightweight, and having excellent heat dissipation
characteristics.
[0008] The battery module disclosed in Patent Document 1 comprises
battery cells housed in a case, where a resin layer exists between
the battery cells and the case. This resin layer is formed by
injecting a curable resin composition through the injection port
formed in the case and then curing it in the manufacturing
processes.
[0009] However, in the course of injecting the curable resin
composition, the internal pressure in the case rises, but while the
increased internal pressure is relieved after the injection
process, a phenomenon occurs, in which the injected curable resin
composition is discharged out of the injection port again (see FIG.
1). The curable resin thus reversely discharged needs to be removed
by a separate process.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a photograph showing a reverse discharge
phenomenon.
[0011] FIG. 2 is a diagram showing an exemplary module case.
[0012] FIG. 3 is a diagram showing a form in which battery cells
are housed in a module case.
[0013] FIG. 4 is a diagram of an exemplary bottom plate in which
injection ports and observation holes are formed.
[0014] FIGS. 5 and 6 are diagrams showing an exemplary battery
pouch that may be used as a battery cell.
[0015] FIGS. 7 and 8 are diagrams showing the structure of an
exemplary battery module.
[0016] FIG. 9 is a schematic diagram in the form that a tape is
attached so as to cover an injection port.
[0017] FIG. 10 is a schematic diagram of a process of mounting an
injection device to an injection port, and FIG. 11 is a diagram
showing an injection device mounted on an injection port.
[0018] FIG. 12 is a schematic diagram of a case where a penetrating
auxiliary portion is formed on a tape.
DISCLOSURE
Technical Problem
[0019] The present application provides a method for manufacturing
a battery module. It is an object of the present application to
provide a manufacturing method capable of solving a process delay
or contamination of a case and the like due to a reverse discharge
phenomenon that occurs when a curable resin composition is injected
into an injection port.
Technical Solution
[0020] Among physical properties mentioned in this specification,
when the measured temperature affects the result, the relevant
physical property is a physical property measured at room
temperature, unless otherwise specified. The term room temperature
is a natural temperature without warming or cooling, and usually a
temperature in a range of about 10.degree. C. to about 30.degree.
C., or about 23.degree. C. or about 25.degree. C. or so. In
addition, unless otherwise specified herein, the unit of
temperature is .degree. C.
[0021] Among physical properties mentioned in this specification,
when the measured pressure affects the result, the relevant
physical property is a property measured at normal pressure, unless
otherwise specified. The term normal pressure is a natural pressure
without being pressurized or depressurized, and usually about 1 atm
or so is referred to as normal pressure.
[0022] Hereinafter, first, the structure of the battery module
manufactured by the manufacturing method of the present application
will be described.
[0023] The battery module manufactured in the present application
comprises a module case and a battery cell, where the battery cell
is housed in the module case. One or more battery cells may be
present in the module case, and a plurality of battery cells may be
housed in the module case. The number of battery cells housed in
the module case is adjusted depending on applications and the like,
which is not particularly limited. The battery cells housed in the
module case may be electrically connected to each other.
[0024] The module case may comprise at least sidewalls and a bottom
plate which form an internal space in which the battery cell can be
housed. The module case may further comprise a top plate for
sealing the internal space. The sidewalls, the bottom plate, and
the top plate are integrally formed with each other, or the
sidewalls, the bottom plate, and/or the top plate as separated from
each other are assembled, so that the module case can be formed.
The shape and size of such a module case are not particularly
limited and may be appropriately selected depending on
applications, and the type and number of the battery cell housed in
the internal space, and the like.
[0025] In this specification, since there are at least two plates
constituting the module case excluding sidewalls, the term top
plate and bottom plate are terms having relative concepts used to
distinguish them. That is, it does not mean that in the actual use
state, the top plate necessarily exists at the upper portion and
the bottom plate necessarily exists at the lower portion.
[0026] FIG. 2 is a view showing an exemplary module case (10),
which is an example of a box-shaped case (10) comprising one bottom
plate (10a) and four sidewalls (10b). As in FIG. 2, the module case
(10) may further comprise a top plate (10c) sealing the internal
space.
[0027] FIG. 3 is a schematic view of the module case (10) of FIG.
2, as observed from above, in which the battery cells (20) are
housed.
[0028] An injection port is formed in the bottom plate, the
sidewalls, and/or the top plate of the module case. Such an
injection port may be formed on the bottom plate or the like which
is in contact with a resin layer to be described below, and may be
formed on the top plate and the bottom plate, and the like which
are in contact with the resin layer. The injection port is formed
for a process of injecting a resin composition forming the resin
layer, as described below. The shape, number and position of the
injection port can be adjusted in consideration of the injection
efficiency of the resin composition. In one example, the injection
port may be formed at least on the bottom plate and the top
plate.
[0029] In one example, the injection port may be formed at about
1/4 to 3/4 point or about 3/8 to 7/8 point, or approximately the
middle, of the total length of the sidewalls, the bottom plate, or
the top plate. By injecting the resin composition through the
injection port formed at this point, the resin layer can be
injected so as to have a wide contact area. Here, as shown in FIG.
4, 1/4, 3/4, 3/8, or 7/8 point is, for example, a ratio of the
distance (A) to the hole forming position relative to the total
length (L) measured based on any one end face (E) of the bottom
plate or the like. The end (E) at which the length (L) and the
distance (A) are formed may be any end (E) as long as the length
(L) and the distance (A) are measured from the same end (E). In
FIG. 4, the injection port (50a) is in a form of being located at
the approximately middle part of the bottom plate (10a).
[0030] The size and shape of the injection port are not
particularly limited, and can be formed in consideration of the
injection efficiency of a resin layer material to be described
below. For example, the injection port may have a circular shape,
an elliptical shape, a polygonal shape such as triangle or square,
or an amorphous shape. The number and spacing of the injection port
are not greatly limited and can be adjusted so that the resin layer
can have a wide contact area with the bottom plate or the like, as
described above.
[0031] An observation hole (for example, 50b in FIG. 4) may be
formed at the end of the top plate and the bottom plate, and the
like where the injection port is formed. For example, when the
resin composition is injected through the injection port, such an
observation hole may be for observing whether the injected
composition is injected well to the end of the sidewalls, the
bottom plate, or the top plate. The position, shape, size, and
number of the observation hole are not limited as long as they are
formed so that it can be confirmed whether the injected material is
properly injected.
[0032] The module case may be a thermally conductive case. The term
thermally conductive case means a case having the thermal
conductivity of the entire case of 10 W/mk or more, or comprising
at least a portion having the thermal conductivity as above. For
example, at least one of the sidewalls, the bottom plate and the
top plate as described above may have the thermal conductivity
described above. In another example, at least one of the sidewalls,
the bottom plate, and the top plate may comprise a portion having
the thermal conductivity.
[0033] In the structure of the battery module according to one
example, a first filler-containing cured resin layer in contact
with the top plate and the battery cell, and a second
filler-containing cured resin layer in contact with the bottom
plate and the battery cell are included, as described below. In
this structure, at least one resin layer of at least the first and
second filler-containing cured resin layers may be a thermally
conductive resin layer, whereby at least the top plate or the
bottom plate in contact with the thermally conductive resin layer
may be thermally conductive, or may comprise a thermally conductive
portion.
[0034] The thermal conductivity of the thermally conductive top
plate, bottom plate or side wall; or the thermally conductive
portion may be about 20 W/mk or more, 30 W/mk or more, 40 W/mk or
more, 50 W/mk or more, 60 W/mk or more, 70 W/mk or more, 80 W/mk or
more, 90 W/mk or more, 100 W/mk or more, 110 W/mk or more, 120 W/mk
or more, 130 W/mk or more, 140 W/mk or more, 150 W/mk or more, 160
W/mk or more, 170 W/mk or more, 180 W/mk or more, 190 W/mk or more,
or about 195 W/mk or more. The higher the value of the thermal
conductivity is, the more advantageous it is from the viewpoint of
the heat dissipation property of the module, and the like, and the
upper limit is not particularly limited. In one example, the
thermal conductivity may be about 1,000 W/mk or less, 900 W/mk or
less, 800 W/mk or less, 700 W/mk or less, 600 W/mk or less, 500
W/mk or less, 400 W/mk or less, 300 W/mk or less, or about 250 W/mk
or less, but is not limited thereto. The kind of materials
exhibiting the thermal conductivity as above is not particularly
limited, and for example, includes metal materials such as
aluminum, gold, pure silver, tungsten, copper, nickel, or platinum.
The module case may be comprised entirely of the thermally
conductive material as above, or at least a part of the module case
may be a portion comprised of the thermally conductive material.
Accordingly, the module case may have the above-mentioned range of
thermal conductivity, or comprise at least a portion having the
aforementioned thermal conductivity.
[0035] In the module case, the portion having a thermal
conductivity in the above range may be a portion in contact with
the resin layer and/or the insulating layer as described below. In
addition, the portion having the thermal conductivity may be a
portion in contact with a cooling medium such as cooling water.
According to this structure, a structure capable of effectively
discharging heat generated from the battery cell to the outside can
be realized.
[0036] The type of the battery cell housed in the module case is
not particularly limited, and a variety of known battery cells may
be applied. In one example, the battery cell may be a pouch type.
Referring to FIG. 5, the pouch type battery cell (100) may
typically comprise an electrode assembly, an electrolyte, and a
pouch exterior material.
[0037] FIG. 5 is an exploded perspective view schematically showing
the configuration of an exemplary pouch type cell, and FIG. 6 is a
combined perspective view of the configuration of FIG. 5.
[0038] The electrode assembly (110) included in the pouch type cell
(100) may be in a form in which at least one positive plate and at
least one negative plate are disposed with each separator
interposed therebetween. The electrode assembly (110) may be a
wound type in which one positive plate and one negative plate are
wound together with the separator, or a stacked type in which a
plurality of positive plates and a plurality of negative plates are
laminated alternately with each separator interposed
therebetween.
[0039] The pouch exterior material (120) may be configured in a
form equipped with, for example, an outer insulating layer, a metal
layer, and an inner adhesive layer. This exterior material (120)
protects internal components such as the electrode assembly (110).
The metal layer of the electrode assembly (110) may comprise a
metal thin film, such as aluminum, to protect inner elements such
as the electrolyte, to complement the electrochemical properties by
the electrode assembly (110) and the electrolyte, and to consider
heat dissipation or the like. Such a metal thin film may be
interposed between insulating layers formed of an insulating
material in order to ensure electrical insulation with elements
such as the electrode assembly (110) and the electrolyte, or other
elements outside the battery (100).
[0040] In one example, the exterior material (120) may comprise an
upper pouch (121) and a lower pouch (122), where in at least one of
the upper pouch (121) and the lower pouch (122), a concave internal
space (I) can be formed. The electrode assembly (110) can be housed
in the internal space (I) of this pouch. A sealing portion (S) is
provided on each outer peripheral surface of the upper pouch (121)
and the lower pouch (122) and these sealing portions (S) are bonded
to each other so that the internal space accommodating the
electrode assembly (110) can be sealed.
[0041] Each electrode plate of the electrode assembly (110) is
provided with an electrode tab, and one or more electrode tabs may
be connected to an electrode lead. The electrode lead may be
interposed between the sealing portions (S) of the upper pouch
(121) and the lower pouch (122) and exposed to the outside of the
exterior material (120) to function as an electrode terminal of the
secondary battery (100).
[0042] The shape of the pouch type cell as described above is only
one example, and the battery cell applied in the present
application is not limited to the above-described kind. In the
present application, various shapes of known pouch type cells or
other types of cells can be all applied as battery cells.
[0043] The battery module of the present application may further
comprise a resin layer. Specifically, the battery module of the
present application may comprise at least a filler-containing cured
resin layer. In the present application, the term filler-containing
cured resin layer is a layer containing a resin component and a
filler. The term cured resin layer means a layer formed by curing a
resin composition having a low viscosity to the extent that it is
in a liquid phase or has sufficient fluidity. Here, the low
viscosity having a liquid phase or sufficient fluidity may mean a
range of about 400 cP or less, or about 100 to about 400 cP (based
on room temperature and a shear rate of 2.5/s). The viscosity is a
result of measurement according to a method of an example to
described below. The lower limit of the viscosity is not
particularly limited as long as the resin composition has a
sufficient low viscosity, but it may be generally about 10Pas or
more. In addition, the viscosity is the viscosity of the resin
composition before curing.
[0044] The battery module may comprise, as the filler-containing
cured resin layer, a first filler-containing cured resin layer in
contact with the top plate and the battery cell, and a second
filler-containing cured resin layer in contact with the bottom
plate and the battery cell.
[0045] In one example, each of the resin layers may also be an
adhesive layer. The term adhesive layer means a case where the
adhesive force of the resin layer is at least 150 gf/10 mm or more,
200 gf/10 mm or more, 250 gf/10 mm or more, 300 gf/10 mm or more,
350 gf/10 mm or more, or about 400 gf/10 mm or more. The adhesive
force is measured for an aluminum pouch according to a method
disclosed in an example to be described below. The upper limit of
the adhesive force of the resin layer is not particularly limited,
which may be, for example, about 2,000 gf/10 mm or less, 1,500
gf/10 mm or less, 1,000 gf/10 mm or less, 900 gf/10 mm or less, 800
gf/10 mm or less, 700 gf/10 mm or less, 600 gf/10 mm or less, or
about 500 gf/10 mm or less or so.
[0046] By forming at least two filler-containing cured resin layers
in the battery module, a battery module having excellent durability
against external impacts or vibrations can be provided.
[0047] In the battery module, at least one of the sidewall, the
bottom plate and the top plate in contact with the resin layer may
be the above-described thermally conductive sidewall, bottom plate
or top plate. On the other hand, in this specification, the term
contact may also mean a case where, for example, the top plate, the
bottom plate and/or the side wall; or the battery cell is in direct
contact with the resin layer, or another element, for example, an
insulating layer or the like exists therebetween. In addition, the
resin layer in contact with the thermally conductive sidewall,
bottom plate or top plate may be in thermal contact with the
target. At this time, the thermal contact may mean a state that the
resin layer is in direct contact with the bottom plate or the like,
or other elements, for example, an insulating layer or the like as
described below, between the resin layer and the bottom plate or
the like are present, but the other element does not interfere with
heat transfer from the battery cell to the resin layer, and from
the resin layer to the bottom plate or the like. Here, the phrase
"does not interfere with heat transfer" means the case that even
when other elements (e.g., an insulating layer or a guiding portion
as described below) exists between the resin layer and the bottom
plate or the like, the total thermal conductivity of the other
elements and the resin layer is about 1.5 W/mK or more, about 2
W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more,
or about 4 W/mk or more, or the total thermal conductivity of the
resin layer and the bottom plate or the like in contact therewith
is included in the range even when the other elements are present.
The thermal conductivity of the thermal contact may be about 50
W/mk or less, 45 W/mk or less, 40 W/mk or less, 35 W/mk or less, 30
W/mk or less, 25 W/mk or less, 20 W/mk or less, 15 W/mk or less, 10
W/mk or less, 5 W/mk or less, 4.5 W/mk or less, or about 4.0 W/mk
or less. This thermal contact can be achieved by controlling the
thermal conductivity and/or the thickness of the other element when
the other element is present.
[0048] Among the curable resin layers, at least a thermally
conductive cured resin layer to be described below may be in
thermal contact with the bottom plate or the like and may also be
in thermal contact with the battery cell. By adopting such a
structure, various fastening parts or cooling equipment of the
module, and the like, which was previously required in the
construction of a general battery module or a battery pack as an
assembly of such modules, is greatly reduced, and simultaneously it
is possible to implement a module in which more battery cells are
housed per unit volume, while ensuring heat dissipation
characteristics. Accordingly, the present application can provide a
battery module having high power while being more compact and
lighter.
[0049] FIG. 7 is an exemplary cross-sectional diagram of the
battery module, and for example, the module may be in a form which
comprises a case (10) including sidewalls (10b) and a bottom plate
(10a); a plurality of battery cells (20) housed inside the case and
a resin layer (30) in contact with both the battery cell (20) and
the case (10), as shown in FIG. 7. FIG. 7 is a diagram of the resin
layer (30) existing on the side of the bottom plate (10a), but the
battery module also comprises a resin layer in the form such as
FIG. 7 on the side of the top plate.
[0050] The contact area between the resin layer and the bottom
plate or the like may be about 70% or more, 75% or more, 80% or
more, 85% or more, 90% or more, or about 95% or more, relative to
the total area of the bottom plate or the like. The upper limit of
the contact area is not particularly limited, and may be, for
example, 100% or less, or less than about 100%.
[0051] When the top plate or the bottom plate is thermally
conductive and the cured resin layer in contact therewith is also
thermally conductive, the thermally conductive portion or the
thermally conductive bottom plate or the like may be a portion in
contact with a cooling medium such as cooling water. That is, as
schematically shown in FIG. 7, the heat (H) can be easily
discharged to the bottom plate or the like by the above structure,
and heat release can be easily performed even in more simplified
structures by contacting this bottom plate or the like with the
cooling medium (CW).
[0052] The first and second cured resin layers may each have a
thickness in a range of, for example, about 100 .mu.m to about 5 mm
or in a range of about 200 .mu.m to about 5 mm. In the structure of
the present application, the thickness of the resin layer may be
set to an appropriate thickness in consideration of the desired
heat dissipation characteristics or durability. The thickness may
be the thickness of the thinnest portion of the resin layer, the
thickness of the thickest portion, or the average thickness.
[0053] As shown in FIG. 7, a guiding portion (10d) which can guide
the housed battery cell (20) may also be present on at least one
surface of the inside of the module case (10), for example, a
surface (10a) in contact with the resin layer (30). At this time,
the shape of the guiding portion (10d) is not particularly limited,
and an appropriate shape can be employed in consideration of the
shape of the battery cell to be applied, where the guiding portion
(10d) may be integrally formed with the bottom plate or the like,
or may be attached separately thereto. The guiding portion (10d)
may be formed using a thermally conductive material, for example, a
metallic material such as aluminum, gold, pure silver, tungsten,
copper, nickel, or platinum in consideration of the above-described
thermal contact. In addition, although not shown in the drawings,
an interleaf or an adhesive layer may also be present between the
housed battery cells (20). Here, the interleaf can act as a buffer
upon charging and discharging the battery cell.
[0054] The resin layer or the battery module, to which the resin
layer is applied, may have at least one or more physical properties
out of physical properties to be described below. Each physical
property to be described below is independent, and any one physical
property does not give priority over other physical properties, and
the resin layer can satisfy at least one or two or more physical
properties as described below.
[0055] In one example, at least one of the first and second
filler-containing cured resin layers may be a thermally conductive
resin layer. In this case, the thermal conductivity of the
thermally conductive resin layer may be about 1.5 W/mK or more, 2
W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more,
or about 4 W/mK or more. The thermal conductivity may be about 50
W/mK or less, 45 W/mK or less, 40 W/mK or less, 35 W/mK or less, 30
W/mK or less, 25 W/mK or less, 20 W/mK or less, 15 W/mK or less, 10
W/mK or less, 5 W/mK or less, 4.5 W/mK or less, or about 4.0 W/mK
or less. When the resin layer is a thermally conductive resin layer
as above, the bottom plate, the top plate and/or the sidewall, and
the like to which the resin layer is attached may be a portion
having the above-described thermal conductivity of about 10 W/mK or
more. At this time, the module case portion representing the
thermal conductivity may be a part in contact with a cooling
medium, for example, cooling water or the like. The thermal
conductivity of the resin layer is, for example, a value measured
according to ASTM D5470 standard or ISO 22007-2 standard. The
method of setting the thermal conductivity of the resin layer in
the above-mentioned range is not particularly limited. For example,
the thermal conductivity of the resin layer may be adjusted by
using a filler having thermal conductivity as the filler contained
in the resin layer.
[0056] It is known that among resin components generally known to
be usable as adhesives, acrylic resins, urethane resins, and
silicone resins have similar heat conduction properties to one
another, and epoxy resins have superior thermal conductivity to
that of these resins, and olefin resins have higher thermal
conductivity than that of the epoxy resins. Therefore, it is
possible to select one having excellent thermal conductivity among
the resins as needed. However, since the desired thermal
conductivity is hardly ensured by only the resin components, it is
also possible to apply a method in which filler components having
excellent thermal conductivity are contained in the resin layer at
an appropriate ratio, as described below.
[0057] In the first and second filler-containing cured resin layers
included in the battery module, both may be thermally conductive
resin layers having the thermal conductivity, and at least one may
be the thermally conductive resin layer. In one example, any one of
the first and second filler-containing cured resin layers may be
the thermally conductive resin layer and the other may be a resin
layer having a low thermal conductivity. Such a structure may be
advantageous to the heat dissipation characteristic of the battery
module.
[0058] In this case, the thermal conductivity of the resin layer
having a low thermal conductivity may be less than about 1.5 W/mK,
1 W/mK or less, 0.8 W/mK or less, 0.6 W/mK or less, 0.4 W/mK or
less, or about 0.2 W/mK or less. Here, the lower limit of the
thermal conductivity is not particularly limited, which may be
about 0 W/mK or more or more than 0 W/mK.
[0059] In the battery module, the resin layer or the battery
module, to which the resin layer is applied, may have a thermal
resistance of about 5 K/W or less, 4.5 K/W or less, 4 K/W or less,
3.5 K/W or less, 3 K/W or less, or about 2.8 K/W. When the resin
layer or the battery module, to which the resin layer is applied,
is adjusted in order to exhibit such a range of thermal resistance,
excellent cooling efficiency or heat dissipation efficiency can be
secured. The method of measuring the thermal resistance is not
particularly limited. For example, it can be measured according to
ASTM D5470 standard or ISO 22007-2 standard.
[0060] After a thermal shock test, for example, a thermal shock
test, one cycle of which is composed of holding the battery module
at a low temperature of -40.degree. C. for 30 minutes, and then
again holding it for 30 minutes after increasing the temperature to
80.degree. C., that the cycle is repeated 100 times, it may be
required for the resin layer to be formed such that the resin layer
cannot be detached or peeled off from the module case or the
battery cell of the battery module or cracks cannot be caused. For
example, when the battery module is applied to a product, such as
an automobile, requiring a long guarantee period (for example,
about 15 years or more in the case of the automobile), performance
may be required in the same level as above to ensure
durability.
[0061] The first and second filler-containing cured resin layers
may be electrically insulating resin layers. In the structure
described above, by exhibiting electrical insulation, the resin
layer can maintain the performance of the battery module and secure
stability. The electrically insulating resin layer may have an
insulation breakdown voltage, as measured according to ASTM D149,
of about 3 kV/mm or more, 5 kV/mm or more, 7 kV/mm or more, 10
kV/mm or more, 15 kV/mm or more, or about 20 kV/mm or more. The
higher the value of the insulation breakdown voltage is, the resin
layer shows more excellent insulation, and thus the voltage is not
particularly limited, but may be about 50 kV/mm or less, 45 kV/mm
or less, 40 kV/mm or less, 35 kV/mm or less, or about 30 kV/mm or
less in consideration of composition of the resin layer or the
like. The insulation breakdown voltage as above may also be
controlled by controlling the insulating property of the resin
component in the resin layer, and for example, the insulation
breakdown voltage can be controlled by applying insulating fillers
in the resin layer. In general, among the thermally conductive
fillers, ceramic fillers as described below are known as a
component capable of ensuring insulation.
[0062] As the first and second filler-containing cured resin
layers, a flame retardant resin layer can be applied in
consideration of stability. The term flame retardant resin layer in
the present application may mean a resin layer showing a V-0 rating
in UL 94 V Test (Vertical Burning Test). This can secure stability
against fires and other accidents that may occur in the battery
module.
[0063] The first and second filler-containing cured resin layers
may have a specific gravity of 5 or less. In another example, the
specific gravity may be about 4.5 or less, 4 or less, 3.5 or less,
or about 3 or less. The resin layer showing the specific gravity in
this range is advantageous for manufacturing a lightweight battery
module. The lower the value of the specific gravity is, the more
advantageous the lightening of the module is, and thus the lower
limit is not particularly limited. For example, the specific
gravity can be about 1.5 or more, or about 2 or more. The
components added to the resin layer can be adjusted so that the
resin layer exhibits the specific gravity in the above range. For
example, when the fillers are added, a method of applying fillers
capable of securing a desired thermal conductivity even at a low
specific gravity, if possible, that is, fillers having a low
specific gravity or surface-treated fillers, and the like may be
used.
[0064] It is appropriate that the first and second
filler-containing cured resin layers do not contain volatile
substances, if possible. For example, the resin layer may have a
ratio of non-volatile components of about 90 wt % or more, 95 wt %
or more, or about 98 wt % or more. Here, the non-volatile
components and the ratio thereof can be specified in the following
manner. That is, the non-volatile content can be defined as the
remaining portion after the resin layer is maintained at
100.degree. C. for about 1 hour, and thus the ratio can be measured
based on the initial weight of the resin layer and the ratio after
the resin layer is maintained at 100.degree. C. for about 1
hour.
[0065] The first and second filler-containing cured resin layers
may have excellent resistance to deterioration, if necessary, but
it may be required to have stability that the surface of the module
case or the battery cell is chemically unreactive, if possible.
[0066] It may be advantageous that the first and second
filler-containing cured resin layers have also a low shrinkage
ratio during the process of curing or after curing. This can
prevent the occurrence of peeling or voids that may occur during
the manufacture or use process of the module. The shrinkage ratio
can be appropriately adjusted within a range capable of exhibiting
the above-mentioned effect, and can be, for example, less than 5%,
less than 3% or less than about 1%. The lower the value of the
shrinkage ratio is, the more advantageous the shrinkage ratio is,
and thus the lower limit is not particularly limited.
[0067] It may be advantageous that the first and second
filler-containing cured resin layers have also a low coefficient of
thermal expansion (CTE). This can prevent the occurrence of peeling
or voids that may occur during the manufacture or use process of
the module. The coefficient of thermal expansion can be
appropriately adjusted within a range capable of exhibiting the
above-described effects, and can be, for example, less than about
300 ppm/K, less than 250 ppm/K, less than 200 ppm/K, less than 150
ppm/K or less than about 100 ppm/K. The lower the value of the
coefficient of thermal expansion is, the more advantageous the
coefficient is, and thus the lower limit is not particularly
limited.
[0068] The tensile strength of the first and second
filler-containing cured resin layers can be appropriately adjusted,
whereby excellent impact resistance and the like can be secured to
provide a module showing appropriate durability. The tensile
strength can be adjusted, for example, in the range of about 1.0
MPa or more.
[0069] The elongation of the first and second filler-containing
cured resin layers can be appropriately adjusted, whereby excellent
impact resistance and the like can be secured to provide a module
showing appropriate durability. The elongation can be adjusted, for
example, in the range of about 10% or more, or about 15% or
more.
[0070] It may be advantageous that the first and second
filler-containing cured resin layers also exhibit an appropriate
hardness. For example, if the hardness of the resin layer is too
high, the resin layer becomes excessively brittle, which may
adversely affect reliability. Also, by controlling the hardness of
the resin layer, the impact resistance and the vibration resistance
can be secured, and the durability of the product can be ensured.
The resin layer may have, for example, a hardness in Shore A type
of less than about 100, 99 or less, 98 or less, 95 or less, or
about 93 or less, or a hardness in Shore D type of less than about
80, 70 or less, about 65 or less, or about 60 or less. The lower
limit of the hardness is not particularly limited. For example, the
hardness in Shore A type may be 60 or more, or the hardness in
Shore D type may be about 5 or more, or about 10 or more. The
hardness of the resin layer usually depends on the type and the
ratio of the fillers contained in the resin layer, and when an
excessive amount of fillers is included, the hardness is usually
increased. However, the resin component included in the resin layer
also affects the hardness, as the silicone resins usually show a
lower hardness than other resins such as epoxy or urethane.
[0071] The first and second filler-containing cured resin layers
may also have a 5% weight loss temperature in a thermogravimetric
analysis (TGA) of 400.degree. C. or more, or an 800.degree. C.
balance may be 70 wt % or more. By such a characteristic, the
battery module can have more improved stability at high
temperature. In another example, the 800.degree. C. balance may be
about 75 wt % or more, 80 wt % or more, 85 wt % or more, or about
90 wt % or more. In another example, the 800.degree. C. balance may
be about 99 wt % or less. The thermogravimetric analysis (TGA) can
be conducted within a range of 25.degree. C. to 800.degree. C. at a
temperature raising rate of 20.degree. C./minute under a nitrogen
(N.sub.2) atmosphere of 60 cm.sup.3/minute. The thermogravimetric
analysis (TGA) results can also be achieved by controlling the
composition of the resin layer. For example, the 800.degree. C.
balance usually depends on the type or ratio of the fillers
contained in the resin layer, and when an excess amount of the
fillers is contained, the balance increases. However, since the
silicone resins generally have higher heat resistance than other
resins such as epoxy or urethane, the balance is higher, whereby
the resin component included in the resin layer also affects the
hardness.
[0072] In one example, the battery module may further comprise an
insulating layer between the module case and the battery cell or
between the resin layer and the module case. FIG. 8 is an example
in which the insulating layer (40) is formed between the resin
layer (30) and the guiding portion (10d) formed on the bottom plate
(10a) of the case. By adding an insulating layer, it is possible to
prevent problems such as an electrical short phenomenon or a fire
due to a contact between the cell and the case by an impact that
may occur during use. The insulating layer may be formed using an
insulating sheet having high insulation and thermal conductivity,
or may be formed by applying or injecting a material exhibiting
insulating properties. For example, in a method for manufacturing a
battery module as described below, a process of forming an
insulating layer may be performed before the injection of the resin
composition. A so-called TIM (thermal interface material) or the
like may be applied in forming the insulating layer. Alternatively,
the insulating layer may be formed of an adhesive material, and for
example, the insulating layer may also be formed using a resin
layer having little or no filler such as thermally conductive
fillers. As the resin component which can be used for forming the
insulating layer, an acrylic resin, PVC (poly(vinyl chloride)), an
olefin resin such as PE (polyethylene), an epoxy resin, silicone or
a rubber component such as an EPDM (ethylene propylene diene
monomer) rubber, and the like can be exemplified, without being
limited thereto. The insulating layer may have an insulation
breakdown voltage, as measured according to ASTM D149, of about 5
kV/mm or more, 10 kV/mm or more, 15 kV/mm or more, 20 kV/mm or
more, 25 kV/mm or more, or about 30 kV/mm or more. The higher the
value of the insulation breakdown voltage is, the better the
insulation shows, and thus it is not particularly limited. For
example, the insulation breakdown voltage of the insulating layer
may be about 100 kV/mm or less, 90 kV/mm or less, 80 kV/mm or less,
70 kV/mm or less, or about 60 kV/mm or less. The thickness of the
insulating layer can be set to an appropriate range in
consideration of the insulating property and the thermal
conductivity of the insulating layer, and the like, and for
example, may be about 5 .mu.m or more, 10 .mu.m or more, 20 .mu.m
or more, 30 .mu.m or more, 40 .mu.m or more, 50 .mu.m or more, 60
.mu.m or more, 70 .mu.m or more, 80 .mu.m or more, or about 90
.mu.m or more or so. In addition, the upper limit of the thickness
is not particularly limited and may be, for example, about 1 mm or
less, about 200 .mu.m or less, 190 .mu.m or less, 180 .mu.m or
less, 170 .mu.m or less, 160 .mu.m or less, or 150 .mu.m or
less.
[0073] An exemplary aspect of the present application relates to a
method for manufacturing a battery module in such a form. That is,
the exemplary manufacturing method may be a method for
manufacturing a battery module which comprises a module case, in
which an internal space is formed by a bottom plate and sidewalls,
and an injection port is formed in the bottom plate or the
sidewalls; a plurality of battery cells existing in the internal
space; and a resin layer in contact with the bottom plate or the
sidewalls while being in contact with the battery cells.
[0074] In the manufacturing method, the specific structure of the
case, the material and the shape thereof, and the details of the
battery cell and the resin layer are the same as already described.
However, the battery module is one example of modules that can be
manufactured by the manufacturing method of the present
application, and the manufacturing method of the present
application can also be applied to the formation of other modules
requiring a similar injection process in the manufacturing
processes, in addition to the above-described module.
[0075] The manufacturing method of the present application
comprises a process of attaching a tape to the injection port
before injecting the resin composition through the injection port.
That is, the manufacturing method may comprise a step of attaching
a tape to cover the injection port of the bottom plate or the
sidewalls. FIG. 9 is a schematic diagram of the bottom plate(100a)
or sidewalls in which the tape (600) is attached to cover the
injection port (500).
[0076] In the manufacturing method of the present application, an
injection device for injecting a resin composition is mounted on
the injection port, following the above steps. In this process, the
injection device may be mounted such that the injection device is
mounted on the injection port while penetrating the tape. Such a
process is schematically shown in FIG. 10, where the process can be
performed by advancing the injection device (700) toward the tape
(600) covering the injection port of the bottom plate (100a) or the
like as in FIG. 10, and as a result, as shown in FIG. 11, while the
tape is torn, the injection device can be mounted on the injection
port by penetrating the tape.
[0077] The type of the injection apparatus to be applied in this
process is not particularly limited, and a nozzle or other devices
capable of injecting the resin composition may be used.
[0078] In the manufacturing method of the present application,
after mounting such an injection device, the resin composition may
be injected into the relevant injection device.
[0079] The above-described reverse discharge phenomenon can be
prevented by this method, or even if the reverse discharge is
caused, it is possible to simply and cleanly remove the material
that has been discharged reversely by removing the tape after
removal of the injection device.
[0080] In the manufacturing method of the present application, the
type of the tape attached to the injection port is not particularly
limited, and a suitable type may be used. For example, the tape may
include paper, a polyester-based polymer film such as polyethylene
terephthalate or polyethylene naphthalate, a cellulose-based
polymer film such as diacetylcellulose or triacetylcellulose, an
acrylic polymer film such as polymethylmethacrylate, a
styrene-based polymer film such as polystyrene or an
acrylonitrile/styrene copolymer (AS resin), a polycarbonate polymer
film or the like. Also, a polyolefin-based polymer film such as
polyethylene, polypropylene, polyolefin having a cyclo- or
norbornene-based structure or an ethylene/propylene copolymer, a
vinyl chloride-based polymer film, an amide-based polymer film such
as nylon or aromatic polyamide, an imide-based polymer film, a
sulfone-based polymer film, a polyethersulfone-based polymer film,
a polyetheretherketone-based polymer film, a
polyphenylenesulfide-based polymer film, a vinylalcohol-based
polymer film, a vinylidene chloride-based polymer film, a
vinylbutyral-based polymer film, an allylate-based polymer film, a
polyoxymethylene-based polymer film, an epoxy-based polymer film,
or a film of a blend of the above polymers or the like can be used.
The attachment step can be performed by forming a known
pressure-sensitive adhesive layer on one surface of such a tape.
Furthermore, the thickness of the film is not particularly limited,
and an appropriate thickness may be selected according to the
purpose.
[0081] In the method of the present invention, a penetrating
auxiliary portion with a smaller size than that of the injection
port may be formed on the tape attached to cover the injection port
may have, and in another example, a step of attaching the tape to
the injection port and then forming the penetrating auxiliary
portion may also be further performed.
[0082] FIG. 12 is an example of the case where the penetrating
auxiliary portion (800) is formed, where this penetrating auxiliary
portion can be performed in a known manner such as a method of
making a cut on a tape.
[0083] The injection device can be mounted in the tape, while
effectively penetrating the tape, by forming such an auxiliary
portion and then mounting the injection device toward the auxiliary
portion.
[0084] In the manufacturing method of the present application, a
series of processes, such as attachment of the tape, installation
of the injection device and injection of the resin composition, may
also be performed in a state where the battery cells are present in
the internal space of the module case, and may also be performed in
a state where they are not present, but generally, it can be
performed in a state where a number of battery cells are present in
the internal space.
[0085] In the manufacturing method of the present application,
following the injection process, a process of removing the tape
that has been attached may be further performed.
[0086] In addition, any necessary process may be further performed,
and for example, in the case where the injected resin composition
is a curable resin, a process of curing the relevant resin
composition may be performed, and as described above, in order to
form a structure in which the first and second resin layers are
simultaneously applied, the above process may be performed through
the injection port of the bottom plate and the same process may
also be repeatedly performed through the injection port of the top
plate.
[0087] The type of the resin composition to be injected in the
above process is not particularly limited, and any kind may be used
as long as it is formulated so as to be capable of forming the
resin layer as described above. For example, the resin composition
may comprise an acrylic resin, an epoxy resin, a urethane resin, an
olefin resin, a urethane resin, an EVA (ethylene vinyl acetate)
resin or a silicone resin, or a precursor thereof.
[0088] The resin composition may be an adhesive material as
described above, and may be a solvent type, a water-based type or a
solventless type, but the solventless type resin layer may be
appropriate in consideration of convenience of the manufacturing
process to be described below, and the like.
[0089] The resin layer material may be an active energy beam curing
type, a moisture curing type, a thermosetting type, a room
temperature curing type, or the like, and the room temperature
curing type may also be appropriate in consideration of the
convenience of the manufacturing process to be described below, and
the like.
[0090] In one example, the resin composition may be a curable resin
composition. For example, for manufacturing the battery module
having the above-described structure, the curable resin composition
is required to have the following physical properties. First, if
necessary, in order to secure thixotropy or thermal conductivity, a
large amount of fillers may be contained in the resin composition,
and in this case, in order to secure injection processability or
the like, it is necessary for the resin composition to exhibit the
sufficiently low viscosity as described above. In addition, if only
the low viscosity is simply shown, it is also difficult to ensure
processability, so that appropriate thixotropy is required, and it
may be necessary that the curing itself progresses at room
temperature while exhibiting excellent adhesive force by
curing.
[0091] In the present application, a urethane resin composition may
be applied as the resin composition securing such characteristics.
That is, the resin layer may be a urethane resin layer, that is, a
resin layer containing a urethane resin as a main component in
resin components.
[0092] The urethane resin composition may be a two-component type
comprising a main composition part containing at least a polyol or
the like; and a curing agent composition part containing at least
an isocyanate compound, and the resin layer may be formed by
compounding such a two-component type to prepare a resin
composition and curing the composition.
[0093] For example, a known mixer such as a static mixer may be
applied to mix the main composition part with the curing agent
composition, and then the mixture may be injected through the
injection device.
[0094] Therefore, the urethane resin layer may comprise at least
the polyol-derived unit and the polyisocyanate-derived unit. In
this case, the polyol-derived unit may be a unit formed by
urethane-reacting the polyol with the polyisocyanate, and the
polyisocyanate-derived unit may be a unit formed by
urethane-reacting the polyisocyanate with the polyol.
[0095] As the urethane resin composition, a resin composition
containing at least a polyol which is amorphous or has low
crystallinity as the polyol contained in the main composition may
be applied for securing the physical properties.
[0096] Here, the term amorphous means a case where a
crystallization temperature (Tc) and a melting temperature (Tm) are
not observed in a DSC (differential scanning calorimetry) analysis,
and at this time, the DSC analysis can be performed in a range of
-80.degree. C. to 60.degree. C. at a rate of 10.degree. C./minute,
which can be measured, for example, by a method of raising the
temperature from 25.degree. C. to 60.degree. C. at the above rate,
lowering it to -80.degree. C. again and raising it to 60.degree. C.
again. Furthermore, the sufficiently low crystallinity herein means
a case where the melting point (Tm) observed in the DSC analysis is
about 20.degree. C. or lower, about 15.degree. C. or lower,
10.degree. C. or lower, 5.degree. C. or lower, 0.degree. C. or
lower, -5.degree. C. or lower, -10.degree. C. or lower, or about
-20.degree. C. or lower. The lower limit of the melting point is
not particularly limited, and for example, the melting point may be
about -80.degree. C. or higher, -75.degree. C. or higher, or about
-70.degree. C. or higher.
[0097] As the polyol as above, an ester-based polyol to be
described below can be exemplified. That is, among the ester-based
polyols, a carboxylic acid-based polyol or a caprolactone-based
polyol, specifically polyol having a structure to be described
below, effectively satisfies the above-mentioned
characteristics.
[0098] Generally, the carboxylic acid-based polyol is formed by a
urethane reaction of a component comprising dicarboxylic acid and
polyol (e.g. diol or triol), and the caprolactone-based polyol is
formed by reacting caprolactone and polyol (e.g. diol or triol),
where the polyol satisfying the above-described physical properties
can be constituted through control of the kind and ratio of each
component.
[0099] In one example, the polyol may be polyol represented by
Formula 1 or 2 below.
##STR00001##
[0100] In Formulas 1 and 2, X is a dicarboxylic acid-derived unit,
Y is a polyol-derived unit, for example, a triol or diol unit, and
n and m are integers.
[0101] Here, the dicarboxylic acid-derived unit is a unit formed by
a urethane reaction of dicarboxylic acid with polyol, and the
polyol-derived unit is a unit formed by a urethane reaction of
polyol with dicarboxylic acid or caprolactone.
[0102] That is, when a hydroxyl group of the polyol and a carboxyl
group of the dicarboxylic acid are reacted, a water (H.sub.2O)
molecule is desorbed by a condensation reaction to form an ester
bond, where after the dicarboxylic acid forms the ester bond by the
condensation reaction, X in Formula 1 above means a moiety
excluding the ester bond moiety, and after the polyol also forms
the ester bond by the condensation reaction, Y is a moiety
excluding the ester bond, and the ester bond is represented in
Formula 1.
[0103] In addition, after the polyol forms an ester bond with
caprolactone, Y in Formula 2 also represents a moiety excluding the
ester bond.
[0104] On the other hand, when the polyol-derived unit of Y herein
is a unit derived from polyol containing three or more hydroxyl
groups such as a triol unit, a structure in which the Y moiety is
branched in the structure of the above formula may be realized.
[0105] The kind of the dicarboxylic acid-derived unit of X in
Formula 1 above is not particularly limited, but it may be any one
unit selected from the group consisting of a phthalic acid unit, an
isophthalic acid-derived unit, a terephthalic acid-derived unit, a
trimellitic acid-derived unit, a tetrahydrophthalic acid-derived
unit, a hexahydrophthalic acid-derived unit, a tetrachlorophthalic
acid-derived unit, an oxalic acid-derived unit, an adipic
acid-derived unit, an azelaic acid-derived unit, a sebacic
acid-derived unit, a succinic acid-derived unit, a malic
acid-derived unit, a glutaric acid-derived unit, a malonic
acid-derived unit, a pimelic acid-derived unit, a suberic
acid-derived unit, a 2,2-dimethylsuccinic acid-derived unit, a
3,3-dimethylglutaric acid-derived unit, a 2,2-dimethylglutaric
acid-derived unit, a maleic acid-derived unit, a fumaric
acid-derived unit, an itaconic acid-derived unit and a fatty
acid-derived unit for securing units and desired physical
properties, and an aliphatic dicarboxylic acid-derived unit is more
advantageous than an aromatic dicarboxylic acid-derived unit in
consideration of the glass transition temperature of the cured
resin layer.
[0106] On the other hand, in Formulas 1 and 2, the kind of the
polyol-derived unit of Y is not particularly limited, but it may be
any one or two or more selected from the group consisting of an
ethylene glycol-derived unit, a propylene glycol-derived unit, a
1,2-butylene glycol-derived unit, a 2,3-butylene glycol-derived
unit, a 1,3-propanediol-derived unit, a 1,3-butanediol-derived
unit, a 1,4-butanediol-derived unit, a 1,6-hexanediol-derived unit,
a neopentyl glycol-derived unit, a 1,2-ethylhexyldiol-derived unit,
a 1,5-pentanediol-derived unit, a 1,10-decanediol-derived unit, a
1,3-cyclohexanedimethanol-derived unit, a
1,4-cyclohexanedimethanol-derived unit, a glycerin-derived unit and
a trimethylol propane-derived unit for securing units and desired
physical properties.
[0107] On the other hand, in Formula 1 above, n is an integer, and
the range may be selected in consideration of desired physical
properties, and may be, for example, about 2 to 10 or 2 to 5.
[0108] Also, in Formula 2 above, m is an integer, and the range may
be selected in consideration of desired physical properties, and
may be, for example, about 1 to 10 or 1 to 5.
[0109] When n and m in Formulas 1 and 2 are excessively large, the
crystallinity of the polyol can be strongly expressed.
[0110] The molecular weight of this polyol may be adjusted in
consideration of desired low viscosity characteristics, durability
or adhesiveness, and the like, which may be, for example, in a
range of about 300 to 2,000. The molecular weight mentioned in this
specification may be, for example, a weight average molecular
weight measured by using GPC (gel permeation chromatograph), and
unless otherwise specified herein, the molecular weight of a
polymer means a weight average molecular weight.
[0111] The kind of the polyisocyanate contained in the curing agent
composition part of the urethane resin composition is not
particularly limited, but it may be advantageous that it is an
alicyclic series in order to secure desired physical
properties.
[0112] That is, the polyisocyanate may be an aromatic
polyisocyanate compound such as tolylene diisocyanate,
diphenylmethane diisocyanate, phenylenediisocyanate,
polyethylenephenylene polyisocyanate, xylene diisocyanate,
tetramethylxylylene diisocyanate, trizine diisocyanate, naphthalene
diisocyanate and triphenylmethane triisocyanate; an aliphatic
polyisocyanate such as hexamethylene diisocyanate,
trimethylhexamethylene diisocyanate, lysine diisocyanate,
norbornane diisocyanate methyl, ethylene diisocyanate, propylene
diisocyanate or tetramethylene diisocyanate; an alicyclic
polyisocyanate such as transcyclohexane-1,4-diisocyanate, isoboron
diisocyanate, bis(isocyanate methyl)cyclohexane diisocyanate or
dicyclohexylmethane diisocyanate; or a carbodiimide-modified
polyisocyanate or an isocyanurate-modified polyisocyanate of any
one or two or more of the foregoing, and the like can be used, but
the application of polyisocyanates other than aromatics is
appropriate.
[0113] The ratio of the polyol to the polyisocyanate in the resin
composition is not particularly limited and is appropriately
controlled so as to enable the urethane reaction thereof.
[0114] In order to incorporate other components, such as a filler
and a flame retardant to be described below, into the resin layer,
desired additives may be compounded to the main composition part
and/or the curing agent composition part of the resin composition
and cured.
[0115] Thus, the resin composition may comprise a filler in
consideration of thermal conductivity, insulation, heat resistance
(TGA analysis) or specific gravity, and the like as described
above. If necessary, through use of an appropriate filler, the
thermal conductivity in the above-mentioned range or the like can
be secured. In one example, the filler included in at least the
thermally conductive filler-containing cured resin layer may be a
thermally conductive filler. In the present application, the term
thermally conductive filler means a material having thermal
conductivity of about 1 W/mK or more, 5 W/mK or more, 10 W/mK or
more, or about 15 W/mK or more. The thermal conductivity of the
thermally conductive filler may be about 400 W/mK or less, 350 W/mK
or less, or about 300 W/mK or less. The kind of the usable
thermally conductive filler is not particularly limited, but a
ceramic filler may be applied in consideration of the insulating
property and the like. For example, ceramic particles such as
alumina, AN (aluminum nitride), BN (boron nitride), silicon
nitride, SiC or BeO may be used. In addition, if the insulating
properties of the resin layer can be ensured, application of a
carbon filler such as graphite may also be considered. The shape or
ratio of the filler contained in the resin composition is not
particularly limited, which may be selected in consideration of
viscosity of the resin composition, possibility of settling in the
resin layer, the desired heat resistance or thermal conductivity,
insulation, a filling effect or dispersion, and the like.
Generally, the larger the size of the filler, the higher the
viscosity of the resin composition and the higher the possibility
that the filler precipitates in the resin layer. Furthermore, the
smaller the size, the thermal resistance tends to be increased.
Therefore, an appropriate type of filler may be selected in
consideration of the above points, and two or more fillers may also
be used, if necessary. Considering the filling amount, it is
advantageous to use a spherical filler, but considering network
formation or conductivity, a filler in a form such as needle-like
morphology or flattened morphology may also be used. In one
example, the resin layer may comprise a thermally conductive filler
having an average particle diameter in a range of about 0.001 .mu.m
to about 80 .mu.m. In another example, the average particle
diameter of the filler may be about 0.01 .mu.m or more, 0.1 or
more, 0.5 .mu.m or more, 1 .mu.m or more, 2 .mu.m or more, 3 .mu.m
or more, 4 .mu.m or more, 5 .mu.m or more, or about 6 .mu.m or
more. In another example, the average particle diameter of the
filler may be about 75 .mu.m or less, 70 .mu.m or less, 65 .mu.m or
less, 60 .mu.m or less, 55 .mu.m or less, 50 .mu.m or less, 45
.mu.m or less, 40 .mu.m or less, 35 .mu.m or less, 30 .mu.m or
less, 25 .mu.m or less, 20 .mu.m or less, 15 .mu.m or less, 10
.mu.m or less, or 5 .mu.m or less.
[0116] The ratio of the filler contained in the thermally
conductive resin layer or resin composition can be selected in
consideration of the characteristics of the resin layer so that the
above-mentioned characteristics, for example, thermal conductivity,
insulation, and the like can be secured. For example, the filler
may be contained in a range of about 50 to about 2,000 parts by
weight relative to 100 parts by weight of the resin component or
the precursor in the resin layer or the resin composition. In
another example, the part by weight of the filler may be about 100
parts by weight or more, about 150 parts by weight or more, 200
parts by weight or more, 250 parts by weight or more, 300 parts by
weight or more, 350 parts by weight or more, 400 parts by weight or
more, 500 parts by weight or more, 550 parts by weight or more, 600
parts by weight or more, or about 650 parts by weight or more.
[0117] Therefore, the ratio of the filler in the resin composition
can be adjusted according to the above details.
[0118] The filler-containing cured resin layer that is not
thermally conductive may also comprise a filler depending on the
purpose, for example, for securing thixotropy. In this case, the
filler need not be thermally conductive, and the ratio thereof is
not required to be particularly large, as long as adequate
thixotropy is ensured.
[0119] The type of the filler included in this resin layer is not
particularly limited, but may be, for example, fumed silica, clay
or calcium carbonate, and the like. Of course, if necessary, the
resin layer or the resin composition may also comprise a small
amount of a suitable kind among the above-mentioned thermally
conductive fillers. The shape or ratio of the filler is not
particularly limited, which may be selected in consideration of the
viscosity of the resin composition, the sedimentation possibility
in the resin layer, the thixotropy, the insulating property, the
filling effect or the dispersibility, and the like. As described
above, a suitable type of filler can be selected in consideration
of the viscosity of the resin composition, the sedimentation
possibility of the filler or thermal resistance, and the like, and
two or more kinds of fillers may also be used, if necessary. In one
example, the average particle diameter of the filler contained in
the resin layer may be in a range of about 0.001 .mu.m to about 80
.mu.m. In another example, the average particle diameter of the
filler may be about 0.01 .mu.m or more, 0.1 or more, 0.5 .mu.m or
more, 1 .mu.m or more, 2 .mu.m or more, 3 .mu.m or more, 4 .mu.m or
more, 5 .mu.m or more, or about 6 .mu.m or more. In another
example, the average particle diameter of the filler may be about
75 .mu.m or less, 70 .mu.m or less, 65 .mu.m or less, 60 .mu.m or
less, 55 .mu.m or less, 50 .mu.m or less, 45 .mu.m or less, 40
.mu.m or less, 35 .mu.m or less, 30 .mu.m or less, 25 .mu.m or
less, 20 .mu.m or less, 15 .mu.m or less, 10 .mu.m or less, or
about 5 .mu.m or less.
[0120] The ratio of the filler contained in the resin layer or the
resin composition having low thermal conductivity can be selected
in consideration of the desired thixotropy and the like. For
example, the filler may be contained in a range of about 100 to
about 300 parts by weight relative to 100 parts by weight of the
resin component of the resin layer or the resin composition.
[0121] The resin layer or the resin composition may further
comprise a viscosity controlling agent, such as a thixotropic
agent, a diluent, a dispersant, a surface treatment agent or a
coupling agent, for adjusting viscosity, if necessary, for example,
for raising or lowering viscosity or for controlling viscosity
depending on shear force.
[0122] The thixotropic agent controls the viscosity of the resin
composition depending on the shear force, whereby the process of
manufacturing the battery module can be effectively performed. As
the usable thixotropic agent, fumed silica and the like can be
exemplified.
[0123] The diluent or dispersant is usually used for lowering the
viscosity of the resin composition, and any of various kinds known
in the art can be used without limitation as long as it can exhibit
the above action.
[0124] The surface treatment agent is for surface treatment of the
filler introduced into the resin layer, and any of various kinds
known in the art can be used without limitation as long as it can
exhibit the above action.
[0125] The coupling agent may be used, for example, to improve the
dispersibility of the thermally conductive filler such as alumina,
and any of various kinds known in the art may be used without
limitation as long as it can exhibit the above action.
[0126] The resin layer or the resin composition may further
comprise a flame retardant or a flame retardant aid agent, and the
like. Such a resin layer or resin composition can form a flame
retardant resin layer. As the flame retardant, various known flame
retardants can be applied without particular limitation, and for
example, solid filler type flame retardants and liquid flame
retardants can be applied. The flame retardant includes, for
example, organic flame retardants such as melamine cyanurate and
inorganic flame retardants such as magnesium hydroxide, but is not
limited thereto.
[0127] When the amount of the filler filled in the resin layer or
the resin composition is large, a liquid type flame retardant
material (TEP, triethyl phosphate, or TCPP,
tris(1,3-chloro-2-propyl)phosphate, etc.) may also be used. In
addition, a silane coupling agent capable of acting as a flame
retardant synergist may also be added.
Advantageous Effects
[0128] The present application can provide a method for
manufacturing a battery module by a simple process and at low cost
without occurrence of a reverse discharge phenomenon.
Mode for Invention
[0129] Hereinafter, the battery module of the present application
will be described through examples and comparative examples, but
the scope of the present application is not limited by the scope as
set forth below.
[0130] 1. Viscosity of Resin Composition
[0131] The viscosity of the resin composition was measured at room
temperature and a shear rate condition of from 0.01 to 10.0/s using
a rheological property measuring machine (ARES). The viscosity
mentioned in the examples is a viscosity at a point of a shear rate
of 2.5/s, where a TI (thixotropic index) can be determined through
a ratio of a viscosity at a point of a shear rate of 1.0/s to a
viscosity at a point of a shear rate of 10.0/s.
EXAMPLE 1
[0132] Preparation of Resin Composition
[0133] As a resin composition, two-component urethane adhesive
composition was used. A main composition (viscosity: about 350,000
to 400,000 cP, based on room temperature and a shear rate of 2.5/s)
comprising, as a caprolactone polyol represented by Formula 2
above, a polyol, wherein the number of repeating units (m in
Formula 2) is in a level of about 1 to 3 or so and as the
polyol-derived unit (Y in Formula 2), ethylene glycol and propylene
glycol units are included, was used as the main composition, and a
composition comprising polyisocyanate (HDI, hexamethylene
diisocyanate) was used as the curing agent composition (viscosity:
about 270,000 to 300,000 cP, based on room temperature and a shear
rate of 2.5/s). In order to ensure thixotropy, calcium carbonate as
a filler was divided and compounded in the same amount into the
main and curing agent compositions so that the weight ratio was
about 280 parts by weight or so relative to 100 parts by weight of
the total solid content of the main and curing agent compositions.
For the formation of the resin layer, the main and curing agent
compositions were compounded while adjusting their equivalents and
used. The viscosity of each of the main and curing agent
compositions described in examples is the viscosity in a state
where the filler is compounded.
[0134] Manufacture of Battery Module
[0135] As a module case having the same shape as FIG. 2, a module
case having a bottom plate, sidewalls, and a top plate, made of
aluminum, was used. Guiding portions for guiding installation of
battery cells were formed on the internal surface of the bottom
plate in the module case, injection ports (50a) for injecting the
resin composition were formed at regular intervals in the central
part of the bottom plate in the module case, and observation holes
(50b) were formed at the end, as shown in FIG. 4. A bundle of
pouches laminating a plurality of battery pouches was housed in the
module case. Subsequently, the top plate was covered on the upper
surface of the module case. Thereafter, as shown in FIG. 9, a tape
(600) was attached so as to cover the injection port (500) of the
bottom plate (100a), and a small cut was made at the center thereof
to form an auxiliary portion as shown in FIG. 12. Here, as the tape
(600), a tape, in which an acrylic pressure-sensitive adhesive was
formed on one side of a PET (poly(ethylene terephthalate)) film
having a thickness of about 30 .mu.m to about 50 .mu.m or so, was
used.
[0136] Subsequently, the injection nozzle was moved toward the cut
portion of the tape in the manner shown in FIG. 10 and mounted in
the form shown in FIG. 11, and then the resin composition was
injected. The injection was performed until it was confirmed that
the resin composition to be injected reached the observation holes.
After the injection was completed, the injection device was removed
and then the tape was also removed.
[0137] As a result, there was no component of the resin composition
which was reversely discharged to the injection port portion, and
this series of processes took place in less than 20 seconds.
COMPARATIVE EXAMPLE 1
[0138] A battery module was manufactured in the same manner as in
Example 1, except that the tape was not attached and the resin
composition was injected using the injection device directly. As a
result, the reverse discharge phenomenon as shown in FIG. 1 was
observed. Here, in the process of removing the reversely discharged
resin composition with a solvent, the surface of the case was
scratched by the filler in the resin composition, and thus a
phenomenon that the case surface was changed to black was observed,
and the time for the removal took 20 minutes or more.
COMPARATIVE EXAMPLE 2
[0139] A tape was attached in the same manner as in Example 1, but
a hole was previously perforated in the tape in accordance with the
shape of the injection port and the tape was attached so that the
perforated hole matched the injection port. That is, in the above
example, the tape was not covered with the injection port. In this
way, the resin composition still remained around the injection port
was also observed, and in the process of removing the resin
composition, the surface of the case was also scratched by the
filler in the resin composition, and thus a phenomenon that the
case surface was changed to black was observed. In addition, the
amount of the residual resin composition was smaller than that of
Comparative Example 1, so that the time for removal was shortened,
but it also took about 10 minutes.
* * * * *